Remember that one time when rats killed off half of Europe? And we're now discussing how best to hug them until they go night-night?
I do believe in compassion for animals. That means we take no pleasure in their deaths, and protect them from suffering beyond what's necessary for our civilization. I buy cage-free eggs, for example. But humanity must have two aspects - a hand of love, and a fist of justice. Rats are up there with mosquitoes in terms of existential threats to us, so isn't it obvious which side of us they should see?
I am lucky enough to have never seen a rat, in person, in my 37 years, and I realize they are probably important in natural ecosystems. But even still, inside of our settlements, no method of dealing with them would feel off-limits to me. When I first read the headline of this story, I assumed the rats were somehow being tricked into eating the dry ice, and later exploding. I thought, "oh, that's clever! I guess that's why it's on Slashdot."